Design pipelines to run sequentially

tliljekvist - The Tail snap is actually very light-weight, simply waiting for and returning the last document encountered before end of input.  When you call the Triggered Task, does the pipeline that it calls have any open output views that the REST Get snap would be waiting for a response from?  If the pipeline is returning a large amount of data through an open output view, that could be one issue.  If it does not have any open output views, then the REST Get would wait for that child to complete before allowing the calling pipeline to complete, functioning more like a Pipeline Execute.  You can resolve this by adding a Mapper in the called pipeline with no input view and an open output view with a simple response that the pipeline has started.  This allows the REST Get to receive an immediate response and close out.

However, the recommended pattern for job dependencies is to use an enterprise scheduling tool, such as Autosys, Control-M, Tidal, etc.  Most schedulers would be able to call the triggered tasks and wait for completion before calling the next job.  There is a help page for configuring schedulers to work with long-running tasks.

Hope this helps!